1. Field of the Invention
The present invention relates to a protection circuit.
2. Description of the Related Art
One of major causes of defects in an integrated circuit is damage to a semiconductor element, an electrode, or the like due to electrostatic discharge (hereinafter referred to as ESD). Thus, in order to prevent an integrated circuit from being damaged due to ESD, a protection circuit is provided between a terminal and the integrated circuit. A protection circuit refers to a circuit for preventing overvoltage applied to a terminal due to ESD or the like from being supplied to an integrated circuit.
As for a protection circuit of a signal line, a technique for preventing overcurrent from flowing into an integrated circuit when a signal line terminal has a potential between that of a high potential power supply terminal (VDD) and that of a low potential power supply terminal (VSS) is disclosed in Patent Document 1.